<A NAME=FREEOF>
<TITLE>FREEOF</TITLE></A>
<b><a href=r37_idx.html>INDEX</a></b><p><p>
<B>FREEOF</B> _ _ _ _ _ _ _ _ _ _ _ _ <B>operator</B><P>
<P>
The <em>freeof</em> logical operator returns
<A HREF=r37_0122.html>true</A> if its first argument does
not contain its second argument anywhere in its structure.
<P> <H3>
syntax: </H3>
<P>
<P>
<em>freeof</em>(<expression>,<kernel>) or
<expression> <em>freeof</em> <kernel>
<P>
<P>
<P>
<expression> can be any valid scalar REDUCE expression, <kernel> mus
t
be a kernel expression (see <em>kernel</em>).
<P>
<P>
<P> <H3>
examples: </H3>
<P><PRE><TT>
a := x + sin(y)**2 + log sin z;
2
A := LOG(SIN(Z)) + SIN(Y) + X
if freeof(a,sin(y)) then write "free" else write "not free";
not free
if freeof(a,sin(x)) then write "free" else write "not free";
free
if a freeof sin z then write "free" else write "not free";
not free
</TT></PRE><P>Logical operators can only be used in conditional expressions such
as
<P>
<P>
<em>if</em>...<em>then</em> or <em>while</em>...<em>do</em>.
<P>
<P>
<P>